Pawl adjustment means in an electronic timepiece



y 27,1969 R. FROSSARD ET AL. 3,446,006

PAWL ADJUSTMENT MEANS IN AN EL ECTRONIC TIMEPIECE Filed July 5, 1967 Sheet orz May 27, 1969 R. FROSSARD ETAL PAWL ADJUSTMENT MEANS IN 'AN ELECTRONIC TIMEPIECE Filed July 5I 1967 Free United States Patent US. CI. 58-23 9 Claims ABSTRACT OF THE DISCLOSURE Electronic timepiece having means for adjusting the pressure with which the driving pawl or click acts with the ratchet wheel, means for adjusting the pressure with which the return pawl acts on the ratchet wheel and means for bringing into phase the beaks of the driving and return pawls.

The invention has for its object an electronic timepiece the time standard of which and the driving motor of which are constituted by a mechanical resonator electrically maintained and driving a ratchet wheel by means of a driving pawl rigid with the resonator, a return pawl preventing the rotation of the ratchet wheel in the opposite direction.

In timepieces of this type, the absolutely satisfactory functioning of the device for transforming the oscillatory movement into a rotatory movement by the pawls and the ratchet wheel is only obtained under well defined conditions of pressure and penetration of pawls in the teeth of the ratchet wheel, as well as with a relative positioning, or determined phase of the driving and return pawls. In order to have a uniform movement of the ratchet wheel, it is in effect necessary that when the driving pawl is at the end of its path, the return pawl be halfway between the end and the bottom of a tooth of the ratchet wheel. Even when the parts and the assembly are very accurate, it is very difiicult to satisfy these conditions simultaneously.

The invention precisely has for its object to meet these requirements. To this effect, the timepiece according to the invention is characterized by the fact that it comprises means for adjusting the pressure with which the driving pawl acts with the ratchet wheel, means for adjusting the pressure with which the return pawl acts on the ratchet wheel and means for placing into phase the beaks of the driving and return pawls.

The accompanying drawing shows by way of example two modifications of the object of the invention.

FIGURE 1 shows a first modification in which part of the adjustment occurs by elastic deformation.

FIGURE 2 shows a second modification in which a part of the adjustment occurs by plastic deformation.

On FIGURE 1 is partially shown an electronic timepiece movement comprising essentially a resonator 1 secured by its foot In on a plate 2. The resonator comprises two branches 1b and whose movements are electrically maintained by means of transducers not shown. Branch 1b has a driving pawl 3 which is not directly encased in the branch of the resonator but in a small rectangular bar 4 secured on the resonator by means of a pin 5 located at one of the extremities of bar 4 in order to be able to move rotationally under the action of the lateral force exerted on the free extremity of bar 4. Driving pawl 3 engages in the teeth of a ratchet wheel 6 the pinion of which 7 is constituted by a magnetized polar wheel driving magnetically a magnetic wheel 8, the pinion of which, 9, meshes with a first intermediate wheel 10 driving the rest of the gears of the movement.

Wheels 6 and 8 are pivoted in an auxiliary cage formed by two bridges 11 and 12 secured respectively on the upper and lower surface of foot 112 of the resonator.

Between bridges 11 and 12 is also mounted support 13 of return pawl 14. This support 13 is pivoted at 15 in bridge 11 and bears by its arm 16 against a shoulder 17 located at the extremity of an extension 18 of auxiliary bridge 11. Arm 16 is kept applied against shoulder 17 by a screw 19. Return pawl 14, mounted parallel to driving pawl 3, is encased by forming an elbow with the extremity of a branch 20 of support 13 connected to this support by a narrowed section 21 permitting to move elastically branch 20 by means of a screw 22 the threads of which engage in the central part of support 13. This support is moreover elastically held against bridge 11 by a washer 22 placed under the head of a screw 23' connecting bridge 11 to support 13.

The mounting of the pawls permits to efiect three adjustments: the adjustment of the pressure of the spring of the driving pawl, the adjustment of the pressure of the spring of the return pawl and the putting into phase of the beaks of the driving and return pawls.

Adjustment 0 the pressure of the spring of the driving pawl This adjustment takes place by making bar 4 pivot around its pivot 5 by means of a suitable tool 23, shown Adjustment of the pressure of the spring of the return pawl This adjustment is obtained by varying the arrow of the spring of pawl 14 by the angular movement of its encasing point. The fine adjustment of this movement is ensured by the elastic deformation of the narrowed section 21 of branch 20 of support 13 by means of screw 22, the head of which bears against branch 20 and the threaded part of which is screwed in the rigid body of support 13. The position of the inflexion point of the flexible part 21 is such that the trajectory described by the beak of the pawl under the effect of the movement of the encasing point of its spring comes as near as possible to normal to the point of contact with the wheel.

Putting into phase of the beaks of the pawls The putting into phase of the beaks of the pawls 3 and 14 is obtained by the tangential movement on the ratchet wheel 6 of the beak of the return pawl 14 relative to the beak of driving pawl 3.

This movement is obtained by the rotation of support 13 around pivot 15 and its adjustment 5 ensured by the elastic deformation of branches 16 and 18 under the action of screw 19 the head of which bears against branch 16 and the threaded part of which is screwed in branch 18 of bridge 11. Branches 16 and 18 deform elastically by approximately the same amount.

The fine adjustments of the return pawls taking place only by elastic deformation permit to obtain a very great precision in adjustment.

In the embodiment shown on FIGURE 2 in which will be found most of the elements shown on FIGURE 1, designated by the same reference characters, the adjust- 3 ment of the pressure of the spring of the return pawl and the putting into phase of the beaks of the pawls takes place not by elastic deformation of the support of the retaining pawl but by plastic deformation of certain of its arts.

p Support 25 of return pawl 14 is here rigidly secured its base 26 to the upper bridge 11 of the auxiliary cage by two screws 27 and 28. Support 25 comprises essentially two parts 29 and 30, part 29 being connected to foot 26 by a diminished section 31, while part 30 is connected to part 29 by a diminished section 32. Return pawl 14 is encased forming an elbow in part 30. Parts 29 and 30 also have an elongated slot 33, respectively 34, permitting the introduction of a tool which by rotation permits to deform plastically the support around an inflexion point located respectively in diminished sections 31 and 32.

The adjustment of the pressure of the spring of the return pawl takes place by plastic deformation of the diminished section 32, the position of the point of inflexion of this part being such that the trajectory described by the beak of the pawl under the effect of the movements of the point of encasement of its spring reaches as closely as possible the normal to the point of contact with the wheel.

The putting into phase of the beaks of the pawls occurs by plastic deformation of the diminished section 31, the inflexion point of this deformation being located, as in the first embodiment, on the extension of the line passing by the contact point of pawl 14 with ratchet wheel 6 and the centre of this wheel, in such a way that the beak of pawl 14 moves tangentially on the ratchet wheel.

The upper bridge 11 has further more an opening per mitting to introduce vertically a tool in slot 33.

FIGURES 1 and 2 naturally only show two typical types of adjustment by elastic deformation of the material. The important thing is to avoid adjustments by relative movement of two independent pieces one with respect to the other, movements which, even if made with the aid of a micrometer screw, would not give a sufiicient accuracy.

It should be noted with respect to FIGURE 1 that there is provided a half moon-shaped porthole 35 through which it is possible to observe the teeth of rachet wheel 6.

The half-moon shape given to this porthole makes it possible not to weaken the extremity of bridge 11 and to maintain the correct support of the setting of pinion 7 in the bridge.

This would not be the case if the half-moon shaped window was replaced by a slot made at the end of the bridge. In this case in effect the setting would only be maintained by the elasticity of the two jaws thus made.

What is claimed is:

1. Electronic timepiece having a time base and a driving member constituted by a mechanical resonator electrically upkept, said resonator having a driving pawl, a ratchet wheel driven in a given direction by said driving pawl, a retaining pawl preventing rotation of said rachet wheel in a direction opposite to said given direction, means for regulating the pressure of said driving pawl on said ratchet wheel, means for adjusting the pressure of said retaining pawl on said ratchet wheel and means for putting into phase said driving .and said retaining pawls.

2. Timepiece according to claim 1, wherein said means for adjusting the pressure of said driving pawl consist of a lever, said lever being secured to said resonator and carrying said driving pawl, and an opening in said resonator near said arm, for inserting a key serving to angularly move said lever so as to modify the tension of a spring associated with said pawl.

3. Timepiece according to claim 1, wherein said means for adjusting the pressure of said retaining pawl consist of an elastically deformable support for said retaining pawl.

4. Timepiece according to claim 1, wherein said means for adjusting the pressure of said retaining pawl consist of a plastically deformable support for said pawl.

5. Timepiece according to claim 3, wherein said pawl has a beak and said support for said pawl has an inflexion point during deformation such that said beak has a trajectory at least approximately perpendicular to said rachet wheel.

6. Timepiece according to claim 3, wherein said support for said retaining pawl has an elastic slot, whereby the parts of said support located on either side of said slot can be brought near each other by means of an adjusting screw.

7. Timepiece according to claim 4, wherein the extremity of said support carrying said retaining pawl has a slot in which can be introduced a tool in order to make the same turn.

8. Timepiece according to claim 1, wherein said means for replacing said pawls in phase consist of an elastically deformable support for said retaining pawl, said support having an arm with an extremity bearing a fixed point, and a middle part bent by means of a screw, and another fixed point where said support is fixed, this point being at least approximately on an extension of a diameter passing on the leading edge of the retaining pawl and the centre of said ratchet wheel.

9. Timepiece according to claim 1, wherein said means for placing in phase said pawls consists of a plastically deformable support for said retaining pawl, said support being pivotalble about an inflexion point located at least approximately on an extension of a diameter passing by the leading edge of said retaining pawl and the centre of said ratchet wheel.

References Cited UNITED STATES PATENTS 2,177,367 10/1939 Klopsteg 58-23 RICHARD B. WILKINSON, Primary Examiner.

EDITH C. SIMMONS, Assistant Examiner.

US. Cl. X.R. 58-2 

